It is feasible for products used under extreme environments such as high-temperature and high-pressure environments to deteriorate with respect to temperature and pressure, and therefore periodic inspections are carried out. These products are produced using expensive materials such as heat-resistant alloys that are able to withstand extreme environments, leading the products to being used in cycles of use and repair until it is determined that the products have reached their lifespan.
Furthermore, high-temperature components are employed in rotation so to speak, in which the high-temperature components are replaced with spare components or are replaced with repaired components. Rotation is not carried out only with pre-prepared spare components in the same device but also with pre-prepared spare components in a different device or with repaired components of the same or different device. For example, in the case in which a high-temperature component a1 of a device A is subjected to a periodic inspection, rotation is carried out in which the high-temperature component a1 is replaced with a pre-prepared spare component in the device A, or is replaced with a repaired component b1 that has been repaired at a prior periodic inspection of another device B, or the like. With this kind of rotation operation, a high-temperature component is efficiently used until reaching the lifespan thereof, reducing the cost and the like borne by the user.